How to beat potato anthracnose

Anthracnose on potato tubers belongs to the group of fungal diseases and affects the culture mainly during hot and dry summers. This disease has other names - dartrosis, black rot of tubers. The defeat of the aboveground part of the plants leads to the premature death of the tops, the infected tubers rot during storage. Experts predict an increase in the harmfulness of anthracnose in the near future.

Causes of the disease

Anthracnose is considered a serious and widespread disease. Its causative agent is a pathogenic fungus of the genus Colletotrichum orbiculare. The disease is transmitted to neighboring plants by insects, wind, rain, dew. Black rot of tubers also spreads through infected planting material.

The main reasons for the incidence of anthracnose potatoes are:

• non-observance of the rules of crop rotation;
• refusal from pre-planting seed processing;
• high acidity of the soil;
• lack of elements in the soil such as phosphorus and potassium;

An outbreak is common in dry and hot weather. Mechanical damage to potato stems contributes to the introduction of fungal spores - the pathogen penetrates through the wounds and gradually affects the whole plant.

Anthracnose is more common in varieties with early ripening and weakened specimens.

The disease can affect other cultures as well. Tomatoes, peppers, tobacco, physalis are susceptible to dartose.

The optimum temperature for the development of the disease is + 18–22 ° С. Anthracnose often affects potato bushes that suffer from dry fusarium rot and late blight. The mycelium, when penetrating into healthy tissue, releases toxins, which entails the manifestation of symptoms of the disease.

Symptoms of anthracnose on potatoes

The manifestations of the disease often become noticeable in the second half of the growing season. The following symptoms begin to appear on potato plantings:

• Darkening of the leaves occurs. The edges of the leaf plates dry up and curl.
• The tops begin to turn yellow, then gradually turn brown, which leads to its premature drying.
• The stems are covered with light brown spots, and later - with vertical stripes.
• On tubers, the fungus manifests itself as vague dark brown spots.
• At high humidity, the affected tubers begin to soften and become slimy.
• The stems wither, the roots look rotten.
• In the future, the insides of diseased tubers acquire a mushy, slimy consistency, vegetables begin to smell unpleasant.
• On the cut of infected stored tubers, the disease manifests itself in the form of annular necrosis (dead vascular bundles located in a circle).

The initial stage of the disease is often confused with dry fusarium rot, however, with anthracnose, the spots on the tubers are darker. In rainy weather, the disease has symptoms typical of wet rot. Diseased specimens are easily pulled out of the soil due to root damage. The pathogen remains in infected vegetables until the next season. The fungus is also preserved in the soil and plant residues.

In storage facilities, tubers are infected from each other, the infection penetrates into them at the points of stolon attachment. First, a depressed spot appears in this place, the area of ​​which increases rapidly, the tissue turns black, becomes covered with sclerotia (oblong or rounded growths containing fungal spores).

Affected potato specimens are unsuitable for planting. They will either give life to diseased plants, or they will not germinate at all.

Effective control methods

Diseased plants can no longer be cured, therefore it is important to pay attention to maintaining the health of the bushes without signs of damage. Sick specimens are destroyed, and healthy bushes are treated with drugs that have a fungicidal effect. You can use a solution of copper sulfate (50 g of substance per 10 l of water) or Bordeaux liquid to spray plants.

Fungicides of the new generation have proven themselves well in the fight against anthracnose:

• Ridomil Gold;
• "Previkur";
• Fundazol;
• "Acrobat MC";
• Proit Gold;
• "Ordan";
• "Speed".

The causative agent eventually develops resistance (resistance) to the active substance, therefore it is advisable to alternate the drugs without using the same remedies from season to season.

Traditional methods of dealing with anthracnose are ineffective. If an outbreak of the disease occurred on the site in the current season, you should take care of preventive measures in order to preserve the harvest as much as possible next year.

Preventive measures to protect culture

Before storing potatoes, it is necessary to sort the tubers, carefully examining each potato so that only healthy vegetables get into the basement. It is important to maintain the correct temperature regime in the storage (+ 2–3 ° C): in a cool environment, the vital processes of the fungus slow down.

After harvesting, it is necessary to remove the tops and other plant debris from the site. Next, a deep plowing of the residues should be performed. In the spring, the soil must be loosened and weeds (especially those belonging to the nightshade family) are removed.

For planting, only healthy material is used, but even in this case, the tubers should be pickled by soaking them in a solution of the drug "Maxim" or "Celest Top".

Due to the fact that the disease develops in the second half of summer, one pre-planting treatment of tubers is not enough. Experts recommend that in case of an increased risk of developing black rot of tubers, lay the preparation "Quadris" or "Uniform" in the furrows during planting. The funds have a protective effect until the harvest.

It will be possible to return potatoes to their original planting site no earlier than in 3-4 years. All related plants belonging to the Solanaceae family will be bad predecessors and followers for this culture.

Good precursors for potatoes are:

• siderates,
• cucumbers,
• cabbage,
• beet,
• greenery.

It is better to choose as followers:

• legumes,
• cabbage,
• pumpkin,
• radish,
• zucchini,
• salad,
• radish,
• onion and garlic.

Prevention measures significantly reduce the risk of developing anthracnose, but do not completely eliminate it. During the entire summer season, you need to closely monitor the plantings, noting any changes in the appearance of the potato bushes. It is important to notice the first signs of the disease in time in order to have time to save the plants that have not yet been affected by it.